Add the ground beef and cook until browned; drain excess fat.
Stir in crushed tomatoes, tomato sauce, Italian seasoning, salt, pepper, and red pepper flakes. Simmer 10–15 minutes to blend flavors.
Meanwhile, cook spaghetti in salted water until al dente; drain well.
In a bowl, whisk the ricotta with the egg, then fold in a portion of the mozzarella and the Parmesan.
In a large mixing bowl, combine the cooked pasta with the meat sauce and ricotta mixture until evenly coated.
Spread the pasta mixture in a baking dish. Top with remaining mozzarella and Parmesan.
Bake until bubbling and the top is golden, about 40–45 minutes. Let rest 10 minutes before slicing.
Notes
A comforting, cheesy baked spaghetti casserole that pairs pasta with beef, crushed tomatoes, ricotta and mozzarella for a family-friendly weeknight main dish.
